Genome instability in AZFc region on Y chromosome in leukocytes of fertile and infertile individuals following exposure to gamma radiation
Men are exposed to various doses of ionizing radiation due to living in regions with high natural background radiation, accidentally, occupationally or for cancer treatment. To study genomic instability of AZFc region to gamma radiation, blood samples from normal, oligozoospermia, and azoospermia individuals were irradiated by a Co-60 source.
Irradiated cells were kept for 48 h in order to repair initial DNA damages. Real time PCR was performed for three markers (SY 1206, SY 1197, SY 579) for testing copy number variation before and after irradiation. Copy number variations were compared by calculation of cycle threshold comparative method.
Copy number variations of studied markers in AZFc region (microdeletion and duplication) in all samples after exposure to radiation increased with a dose dependent fashion. The frequency of instability was significantly higher in samples from infertile men in comparison with fertile ones (p < 0.001).
No significant difference was seen between the two infertile groups (p > 0.05). This observation might be a possible explanation for induction of azoospermia and oligozoospermia after radiotherapy. Increased frequency of induced microdeletion and duplication in infertile men compared with normal might be attributed to the deficiency in repair systems and the genetic factors involved in incomplete spermatogenesis of infertile men.
KeywordsAZFc instability Gamma radiation Infertile men Leukocytes Real time PCR
This work was supported by Research Department of the Faculty of Medical Sciences of Tarbiat Modares University, Tehran, Iran. The authors wish to express their sincere thanks to all patients and healthy individuals for their blood donation and kind contribution and Ms Zahra Tizmaghz for irradiation of samples.
Conflict of Interest statement
The authors declare that there are no conflicts of interest.
- 12.McElreavey K, Krausz C, Bishop CE. The human Y chromosome and male infertility. Results Probl Cell Differ. 2000;28:2211–32.Google Scholar
- 16.Hall EJ. Radiobiology for the radiologist. 5th ed. New York: Lippincott Williams and Wilkins; 2000.Google Scholar
- 23.World Health Organization. WHO manual for the standardized investigation and diagnosis of the infertile couple. Cambridge: Cambridge University Press; 2000.Google Scholar
- 40.Sankaranarayanan K, Wassom JS. Ionizing radiation and genetic risks XIV. Potential research directions in the post-genome era based on knowledge of repair of radiation-induced DNA double-strand breaks in mammalian somatic cells and the origin of deletions associated with human genomic disorders. Mutat Res. 2005;578:333–70.PubMedCrossRefGoogle Scholar